As disclosed in JP H10-24784 A, a technology has been known for monitoring a travelling state of a vehicle and for performing a malfunction diagnostics to various devices equipped to a vehicle. The diagnostics result is remained as vehicle behavior log data.
Recently, in order to monitor malfunction diagnostics performance of the vehicles that have been put on the market, a ratio of the execution number of the malfunction diagnostics to the number of trips of the vehicle is calculated in addition to the diagnostics result. Hereinafter, the ratio of the execution number of the malfunction diagnostics to the number of trips of the vehicle is referred to as a monitoring frequency. For example, one trip means a period from when a controller for controlling the number of trips is powered on to when the controller is powered off. Thus, when the controller for controlling the number of trips is powered on and then is powered off, the controller counts the period as one trip. California Air Resource Board (CARB) published On-Board Diagnostics II (OBD II) that defines a rate-based monitoring law. The rate-based monitoring law requires an equipment of the electronic control apparatus that calculates the monitoring frequency of the diagnostics carried out to the vehicle, and further requires that the monitoring frequency should be higher than a predetermined frequency. In the coming days, in addition to the markets and the areas that are required to adopt the monitoring frequency under the law, the monitoring frequency will be widely used for the on-board diagnostics in other markets and areas.
For example, above-described rate-based monitoring law requires great number of system related items to be diagnosed under the above law. The items related to the system are executed only when the vehicle operates as a system. That is, the system diagnostic requires that the travelling distance of the vehicle is longer than a certain distance, requires the travelling time is longer than a certain period of time, or requires the vehicle travels under a predetermined travelling pattern.
When the travelling of the vehicle ends before the diagnostic of the vehicle is successfully completed caused by a short travel distance or a short travel time, the counting for the number of diagnostics may fail. Thus, the diagnostic, which has not been completed successfully caused by the interruption, may not be counted as one diagnostic. Recently, short distance travel, such as town travel within the town area is increased. Under this circumstance, the monitoring frequency may be decreased caused by the missing count of the diagnostic. Herein, the missing count means the count failure caused by the short travel distance or the short travel time. The decrease of the monitoring frequency may cause an undesirable decrease in the chance to diagnose and evaluate the state of the vehicle and the effect to the environment. Further, regarding the legal aspect, if a law similar to the rate-based monitoring law is made and put into practice in the countries that use vehicles, it is difficult to ensure an observation of the law.